Concerns about End-to-End Congestion Control
The need for end-to-end congestion control:
Floyd, S., and Fall, K.,
Promoting the Use of End-to-End Congestion Control
in the Internet.
IEEE/ACM Transactions on Networking, August 1999.
- B. Braden, D. Clark, J. Crowcroft, B. Davie, S. Deering, D. Estrin, S.
Floyd, V. Jacobson, G. Minshall, C. Partridge, L. Peterson, K.
Ramakrishnan, S. Shenker, J. Wroclawski, L. Zhang,
Recommendations on Queue Management and Congestion Avoidance in the
Available as RFC 2309
text) as an Informational RFC.
Alarm Sounded Over Bandwidth `Greed', James Glave, Wired News,
April 9, 1998. "The next time you see the phrase "highly optimized"
used to sell an Internet application, give a second thought to what it
might be costing the Net."
Multimedia Transmissions Drive Net Toward Gridlock,
Sara Robinson, New York Times, August 23, 1999. "Like a nation's
highway system, the Internet has traffic rules that prevent chaos
and gridlock. But an increasingly popular type of multimedia traffic
is turning out to be a cyber road hog that flouts the rules and
creates traffic jams."
Less conservative congestion control:
This section contains pointers to protocols that might be more
aggressive, in terms of end-to-end congestion control, than
the TCP congestion control mechanisms specified in
on TCP Slow Start, Congestion Avoidance, Fast Retransmit, and
Fast Recovery Algorithms. Some of these protocols might be intended
not for best-effort traffic in the Internet, but only
with accompanying mechanisms that provide additional bandwidth
Multicast: (We note that in the current Mbone, the aggregate
multicast traffic can be limited by a token bucket rate-limiter.)
BoosterWare: "For the Internet community at large, NetBooster
exploits the capacity of the modem to maintain a constant data flow at
its maximum rated speed, regardless of the network traffic load."
Flash Networks Press Release)
From their White Paper on
The BoosterWare Advantage: Enhancing TCP/IP: "BoosterWare, by
contrast, abandons the effort to optimize the window size (a key source
of bottlenecks) during transmissions; instead, window sizes are fixed
according to pre-defined parameters negotiated between the client and
the server once a connection has been established. BoosterWare can be
viewed as a reliable, "no overhead" UDP (user datagram protocol)..."
("RUN Inc. has found a way to squeeze more bandwidth out of existing
TCP/IP networks without changing the network protocols or the
applications that run over them.... In field tests over the Internet,
runTCP has accelerated data transfers by as much four times." -
PC Week Online, Sept. 4, 1997.)
Sitara Networks Inc. ("Everyone talks about the "World Wide Wait",
but no one does anything about it."). As discussed in IP
Acceleration Software: Torquing Up TCP/IP, DataCommunications,
January 1998: "Speedseeker can
selectively suspend the TCP/IP congestion control mechanism when
sending audio and video." See
About Sitara in the News.
"RealAudio 3.0 encoding algorithms have four different fixed data rates
which can be used depending on the bandwidth requirements."
RealPlayer, Windows MediaPlayer, and Quicktime:
S. Hessler and M. Welzl,
An Empirical Study of the Congestion Response of RealPlayer, Windows
MediaPlayer and Quicktime,
"We measured the responsiveness of the three popular streaming media
applications RealPlayer, Windows MediaPlayer and Quicktime with a
varying amount of cross traffic and present a comparison of the
results.... All of the investigated applications were TCP-friendly."
Jae Chung, Yali Zhu, and Mark Claypool,
FairPlayer or FoulPlayer?--Head to Head Performance of RealPlayer
Streaming Video Over UDP versus TCP,
Technical Report N. WPI-CS-tr-02-17, Worchester Polytechnic
Institute Computer Science Department, May, 2002.
"In times of congestion, most RealVideo over UDP
does respond to Internet congestion by reducing
the application layer encoding rate,
often achieving a TCP-Friendly rate.
In times of severe congestion,
RealVideo over UDP gets a proportionately larger share of the
available bandwidth than does the same video over TCP."
Duke P. Hong, Celio Albuquerque, Carlos Oliveira, and Tatsuya Suda,
The Impact of Emerging Streaming Media Applications on TCP/IP,
IEEE Communications, Vol. 39, No. 4, pp. 76-82, April 2001.
media UDP traffic can cause two major maladies in the Internet:
congestion collapse and unfair allocations
of bandwidth among competing traffic flows...
This paper presents simulation
results and empirical measurements that illustrate the congestion
collapse and unfairness maladies, and
ATM ABR's effectiveness in addressing those maladies."
Halo 2 heralds traffic explosion,
BBC News, December 8, 2004.
"The growing popularity of online gaming could spell problems for net
service firms, warns network monitoring company Sandvine."
L. De Cicco, S. Mascolo, and V. Palmisano,
An Experimental Investigation of the Congestion Control Used by Skype
Wired/Wireless Internet Communication, May 2007.
"The explosive growth of VoIP traffic poses a potential
challenge to the stability of the Internet." ...
"We investigate how Skype
behaves in the presence of time-varying available bandwidth." ...
"We have found that Skype flows are somewhat elastic,
i.e. they employ some sort of congestion control when sharing the
bandwidth with unresponsive flows, but are inelastic in the presence of
TCP responsive flows, which provokes extreme unfair use of the available
bandwidth in this case. Finally, we have found that when more Skype
calls are established on the same link, they are not able to adapt their
sending rate to correctly match the available bandwidth, which would
confirm the risk of network congestion collapse."
Last modified: March 2009